Apr 16, 2016
It’s a phenomenon that has, however, puzzled scientists, who have wondered exactly how such lightning is generated. Two new papers, published in Geophysical Research Letters, the journal of the American Geophysical Union (AGU), have helped provide clarity and, in the process, unify two competing schools of thought. (Yes, there are competing schools of thought on volcanic lightning.)
The basics of lightning are understood well enough: Particles within a cloud become electrified, generating a field in which positive and negative charges are separated, and the lightning restores the charges to balance. In thunderstorms, ice crystals are the particles that are electrified. What was unknown was whether ice was also required for volcanic lightning, or whether friction between particles of ash performed that role. The new studies show that both can be true, depending on the situation.
In one study, Alexa Van Eaton, a volcanologist at the U.S. Geological Survey Cascades Volcano Observatory in Vancouver, Wash., and colleagues analyzed lightning during the April 2015 eruption of the Calbuco volcano in Chile, using a global network of lightning sensors.
They found that, far downwind of the volcano, lightning followed the movements of the very top of the ash plume where it was cold enough for ice crystals to develop.
“The lightning basically decoupled from all the other ash particles that were falling to the ground,” said Van Eaton. “Instead, they seem to follow the ice crystals that stayed high in the atmosphere.”
So, mystery solved, right? Ice is after all required for volcanic lightning? Not so fast. Because Van Eaton and her team found that lightning also occurred during a second stage of the eruption, when ash and gas flowed close to the ground, far away from any ice crystals, suggesting that the collision of ash particles alone can create enough of a charge.
That latter finding was reinforced by the second study, in which a team led by Corrado Cimarelli, a volcanologist at Ludwig Maximilian University in Munich, Germany, recorded high-speed video observations of volcanic lightning at Sakurajima volcano on the island of Kyushu, Japan, which has been erupting persistently since 2009. Because ash plumes can obscure the lightning that is taking place within them, Cimarelli and his team also included data from nearby acoustic sensors and electromagnetic field measurements.
They found that during an explosion, particles of ash and debris rub up against each other, which creates a build-up of electrical charge. “Where there is ash violently ejected in the atmosphere, there will be electrical discharges, independent of the magnitude of the eruption,” said Cimarelli.
Read more at Discovery News
Franklin wasn’t lamenting having to pay his taxes. Instead, prior to that passage, Franklin expressed his concerns about the durability of the Constitution, and it makes sense that a scientist would harbor a sense of uncertainty about the document that would guide the major political experiment that was the fledgling republic.
In the sciences, a sure thing is elusive; uncertainty is the norm.
Scientific research is an iterative process. A hypothesis is formulated; research is undertaken; evidence is gathered; results are analyzed. Uncertainty doesn’t mean a lack of understanding so much as it provides opportunities for further study.
As the Union of Concerned Scientists, a scientific advocacy organization, explains in an article about climate change: “To most of us, uncertainty means not knowing. To scientists, however, uncertainty is how well something is known.”
Scientists express their degree of certainty by presenting qualified conclusions based on their results, explaining potential limitations of their methodology and shining a light on potential sources of error for the sake of transparency. Scientific findings have to be reproducible to be reliable, but even that isn’t exactly proof of a theory.
“The very expression ‘scientifically proven’ is a contradiction in terms,” physicist Carlo Rovelli said in a 2012 interview. “There is nothing that is scientifically proven.”
Certainty is described in terms of confidence, and scientists have their own terminology for explaining their level of assurance in their findings. Take the 2012 discovery of the Higgs boson, an elementary particle in the Standard Model of physics first theorized in the 1960s, also known as the “god particle.”
“We observe in our data clear signs of a new particle, at the level of five sigma, in the mass region around 126 GeV,” Fabiola Gianotti, spokeswoman for the Atlas experiment at the LHC, said upon the discovery of the Higgs.
Five sigma is the confidence level required by particle physicists to claim a new discovery, and represents a 1-in-3.5 million probability that the observation is the result of random chance rather than a real effect.
Certainty and probability are related but not necessarily interchangeable terms. Certainty deals with confidence surrounding the facts; probability concerns the likelihood of a particular outcome.
The Intergovernmental Panel on Climate Change (IPCC), for example, uses different terminology to distinguish between facts and forecasts. A statement with a nine out of 10 chance of being true would be described as “very high confidence,” while an outcome with a 90 percent chance of occurring is “very likely.”
Improbable or outlier events don’t necessarily reflect a lack of certainty on the part of the scientists who study them.
To provide a handful of scenarios: There is a 12 percent chance in the next decade that Earth will be hit by a megaflare that causes trillions of dollars in damage.
The Cascadia fault line in the Pacific Northwest has a one-in-three chance of experiencing a major catastrophic earthquake in the next 50 years.
The probability of a caldera-forming eruption at Yellowstone stands around 1 in 730,000 or 0.00014 percent.
The degree of certainty in each of these cases depends on the methodology used and measurements taken by the scientists responsible for the forecasts.
Read more at Discovery News
Apr 15, 2016
While researchers already knew from prior analyses that the winged wonders use two primary bits of input data to navigate – time of day and position of the sun on the horizon – they had no answer for how the butterfly’s brain gathers and processes that information.
Until now, say researchers from the universities of Washington, Michigan and Massachusetts.
In a paper published in the journal Cell Reports, a team from those institutions says it has modeled the neural control mechanisms at work in the butterfly’s brain.
“We wanted to understand how the monarch is processing these different types of information to yield this constant behavior — flying southwest each fall,” said study co-author Eli Shlizerman, an assistant professor at the University of Washington, in a statement.
Monarchs watch the sun, but that’s not enough to get them where they need to go. They also need the time of day. Monarchs, just like people, have a kind of internal clock that keeps track of the daily go-round. Unlike people, though, their clock is centered in the antennae (an appendage humans have so far disdained).
Shlizerman and his colleagues recorded neural signals coming from monarch antenna nerves, to keep track of the clock information, as well as information coming from the insect’s eyes, to account for sun position.
Then they used that data to create a circuit model to show the neural control mechanisms – for the “clock” and “sun position” – that help the butterfly point itself southwest.
The scientists’ model even accounts for how the butterflies get back on course if they stray.
Read more at Discovery News
Built by CEA (French Alternative Energies and Atomic Energy Commission) the devices add to an armory of innovative, non-destructive technologies employed to investigate four pyramids which are more than 4,500 years old. They include the Great Pyramid, Khafre or Chephren at Giza, the Bent pyramid and the Red pyramid at Dahshur.
The project, called ScanPyramids, is scheduled to last one year and is being carried out by a team from Cairo University’s Faculty of Engineering and the Paris-based non-profit organization Heritage, Innovation and Preservation (HIP Institute) under the authority of the Egyptian Ministry of Antiquities.
International researchers from Nagoya University and KEK (High Energy Accelerator Research Organization) in Japan and Laval University, Quebec, Canada, have also joined the project, which is separate from the search for the secret room in King Tut’s tomb.
“Now we welcome new researchers from the Irfu, a CEA fundamental research team,” Mehdi Tayoubi, co-director of the ScanPyramids mission with Hany Helal, professor at Cairo University’s Faculty of Engineering and former minister of research and higher education, said.
Irfu, which stands for Institute of Research into the Fundamental Laws of the Universe, gathers almost 800 researchers on astrophysics, nuclear physics and particle physics.
“These scientists have built dedicated muon telescopes for our mission. They are actually under construction and being tested in the CEA laboratories at Saclay, France,” Tayoubi told Discovery News.
“It is really exciting to see how a technology that just came out from a fundamental research laboratory can help us understand 4,500-year-old massive monuments with non visible physics particles,” he added.
The new muon devices rely on micro-pattern gas detectors called Micromegas. Extremely precise, they are used to reconstruct particles tracks in high energy physics. For example, CEA’s Micromegas have been installed in the Thomas Jefferson National Accelerator Facility.
Such muon telescopes will be used in addition to the infrared thermography, muon radiography, and 3-D reconstruction technologies that have already been employed to investigate the pyramids.
So far the researchers have detected striking thermal anomalies on the eastern and northern side of the Great Pyramid at Giza, which could possibly indicate an unknown cavity or internal structure.
A team led by specialist Kunihiro Morishima, from the Institute for Advanced Research of Nagoya University, Japan, installed 40 muon detector plates inside the lower chamber of the Bent pyramid at Dahshur in an attempt to capture cosmic particles.
The technology relies on the muons that continually shower the Earth’s surface. They emanate from the upper layers of Earth’s atmosphere, where they are created from collisions between cosmic rays of our galactic environment and the nuclei of atoms in the atmosphere.
“Just like X-rays pass through our bodies allowing us to visualize our skeleton, these elementary particles, weighing around 200 times more than electrons, can very easily pass through any structure, even large and thick rocks, such as mountains,” Tayoubi said.
Plate detectors placed inside the pyramid allow researchers to discern void areas — these are places where muons cross without problem — from denser areas where some muons are absorbed or deflected.
While the Japanese muon detectors are used inside the pyramids, the new moun telescopes, using gas detectors, will be used outside the pyramids.
Read more at Discovery News
Regional archaeological services director Stella Chryssoulaki laid out the theory Thursday as she unveiled the findings at the Central Archaeological Council, the custodians of Greece’s ancient heritage.
Given “the high importance of these discoveries”, the council is launching further investigations, the culture ministry said in a statement.
Two small vases discovered amongst the skeletons have allowed archaeologists to date the graves from between 675 and 650 BC, “a period of great political turmoil in the region”, the ministry said.
The skeletons were found lined up, some on their backs and others on their stomachs. A total of 36 had their hands bound with iron.
They were discovered during excavations at an ancient cemetery on Athens’ seaside outskirts, on the construction site of the new National Library of Greece and National Opera.
Archaeologists found the teeth of the men to be in good condition, indicating they were young and healthy.
This boosts the theory that they could have been followers of Cylon, a nobleman whose failed coup in the 7th century BC is detailed in the accounts of ancient historians Herodotus and Thucydides.
Cylon, a former Olympic champion, sought to rule Athens as a tyrant. But Athenians opposed the coup attempt and he and his supporters were forced to seek refuge in the Acropolis, the citadel that is today the Greek capital’s biggest tourist attraction.
Read more at Discovery News
The desert area of Nazca is most famous for giant representations of humans, animals and plants — as well as 900 geometric shapes — carved into the ground: the so-called Nazca lines. But the lines are not the only artifacts of the Nazca civilization, which flourished in the area between 200 BC and 600 AD. The region also contains spiraling, rock-lined holes, known as puquios. Long understood to be a series of underground aqueducts, little else is known about them.
But now, Rosa Lasaponara and a team from the Institute of Methodologies for Environmental Analysis in Italy believe they have some answers. Using satellite imagery, they were able to better understand how the puquios were distributed across the Nazca region.
By considering their positioning relative to water resources and to settlements, they were able to piece together a picture of just how extraordinarily advanced the puquio system was. The corkscrew-shaped tunnels, Lasaponara concluded, funneled wind into a series of underground canals, forcing water to places in the arid region where it was needed.
“The puquios were the most ambitious hydraulic project in the Nasca area and made water available for the whole year, not only for agriculture and irrigation but also for domestic needs,” she told the BBC. “Exploiting an inexhaustible water supply throughout the year, the puquio system contributed to an intensive agriculture of the valleys in one of the most arid places in the world.”
The puquios’ construction, added Lasaponara, “involved the use of particularly specialized technology,” and their maintenance “was likely based on a collaborative and socially organized system, similar to that adopted for the construction of the famous ’Nazca lines‘ which in some cases are clearly related to the presence of water.”
Indeed, one recent theory posits that the lines are in effect a map, pointing to puquios’ locations. As much attention as the lines have deservedly received worldwide over the decades, perhaps it is the puquios that made those lines, and indeed the Nazca civilization, possible.
From Discovery News
Researchers of Brown University in Providence, R.I., have melded observations of Europa with computer models and laboratory experiments to reveal the tidal compression caused by Jupiter’s hefty gravitational field could cause the moon’s fragmented ice to generate more heat than thought, creating exciting new implications for the search for Europan life.
Before NASA’s Voyager and Pioneer flyby missions in the 1970s and then the Galileo mission in the 1990s, we had little clue about the dynamic nature of the Jovian satellites. “(Scientists) had expected to see cold, dead places, but right away they were blown away by their striking surfaces,” said Christine McCarthy, of Columbia University who carried out research into Europa’s ices while a graduate student at Brown University. “There was clearly some sort of tectonic activity — things moving around and cracking. There were also places on Europa that look like melt-through or mushy ice.”
It is now known that Europa possesses an extensive sub-surface ocean of water, protected by a fragmented, icy crust that appears to move much like the continental plates on Earth. Tidal pressures created during Europa’s orbit around Jupiter create an internal dynamo, which gently heats the moon from the core, maintaining the ocean in a liquid state. In addition, the motion of the icy plates are thought to generate their own heat through frictional processes at the boundaries. Much like the heat produced when repeatedly bending a wire coat hanger, heat is dissipated through the repeated tidal flexing of Europa’s crust at these boundaries.
But the small-scale processes behind this tidal dissipation are poorly understood and may have been woefully underestimated.
“People have been using simple mechanical models to describe the ice,” said McCarthy, “they weren’t getting the kinds of heat fluxes that would create these tectonics. So we ran some experiments to try to understand this process better.”
To simulate what might be going on in Europa’s crust, McCarthy headed a project to simulate the tidal pressures that would be felt by Europa’s ice in the lab. Loading ice samples into a compression apparatus at Brown University, the amount of deformation and heating could be measured.
Until now, it has been assumed that the majority of heating comes from friction between individual ice grains, so that would suggest the frictional heating is directly related to the size of the grains. But on varying the ice grain size in her samples, McCarthy noticed no difference in heat flux. Instead, she realized that the bulk of the heating comes from microscopic defects in the ice’s crystalline structure as the ice was deformed. The greater the deformation, the more heat is generated.
“Christine discovered that, relative to the models the community has been using, ice appears to be an order of magnitude more dissipative than people had thought,” said collaborator Reid Cooper of Brown University. “The beauty of this is that once we get the physics right, it becomes wonderfully extrapolative.
“Those physics are first order in understanding the thickness of Europa’s shell. In turn, the thickness of the shell relative to the bulk chemistry of the moon is important in understanding the chemistry of that ocean. And if you’re looking for life, then the chemistry of the ocean is a big deal.”
In short, the realization that the microscopic structure of the ice is generating the heat and that heat generated is way more than can be produced by frictional heating alone, scientists can learn a lot more about the physics of Europa’s icy crust and therefore open a new window into the chemistry of the liquid water ocean below.
Read more at Discovery News
Apr 14, 2016
Historian Agnese Sabato and art historian Alessandro Vezzosi, director of the Museo Ideale in the Tuscan town of Vinci, said they tracked down, one by one, the direct living descendants from Leonardo’s father, a Florentine legal notary named Ser Piero Da Vinci.
“Leonardo’s descendants are all living around Florence and nearby villages such as Empoli and Vinci,” Vezzosi told Discovery News.
It was believed that no traces were left of the painter, engineer, mathematician, philosopher and naturalist. The remains of Leonardo, who died in 1519 in Amboise, France, are believed to have been dispersed in the 16th century during religious wars.
With no Da Vinci’s remains to work on, Sabato and Vezzosi’ starting point was the documents left by Da Vinci’s grandfather, Antonio.
Antonio recorded on a notarial book Leonardo’s birth, indicating his son Ser Piero as Leonardo’s father. There was no mention of the mother’s name.
She is however recorded in one of Antonio’s notes dated 1457, and referred as Caterina, the wife of Achattabriga di Piero del Vaccha da Vinci.
Leonardo’s illegitimate status made even more difficult to reconstruct his family tree.
“We checked documents and tombs as far as France and Spain in order to reconstruct the history of Leonardo’s family,” Vezzosi said.
“We even found a unknown tomb of Leonardo’s family in Vinci,” he added.
Among the Renaissance genius’s relatives are an architect, a policeman, a pastry chef, an accountant and a retired blacksmith.
“I heard this story about our Da Vinci’s blood from my mother, but our family believed it was a legend,” Giovanni Calosi, one of the descendants, said.
Da Vinci’s relatives also include Italian director and producer of operas Franco Zeffirelli, famous for his 1968 version of Romeo and Juliet.
Zeffirelli, whose real name is Gianfranco Corsi, comes from one of the most famous families in Vinci.
“The Corsis related with the Da Vincis in 1794 thanks to the marriage between Michelangelo di Tommaso Corsi and Teresa Alessandra Giovanna di Ser Antonio Giuseppe Da Vinci, direct descendant of Leonardo’s father Ser Piero,” Vezzosi said.
As much as it sounds fascinating, the research presents some weak points. Indeed, the results from archival research could be patchy if one, if not more, false paternities -- where the biological father is not the recorded father -- have occurred somewhere along the 500-year-old male line.
“Regardless of the archival material, there is a strong probability of the male line especially being broken over such a large number of generations. Leonardo was himself illegitimate after all,” historian Kevin Schürer, Pro-Vice-Chancellor for Research at the University of Leicester, told Discovery News.
Schürer found non-paternity, or breaks, when he worked on the genealogy of King Richard III. In that case, genetic research proved that it wasn’t possible to trace a living relative on the male line through the Y chromosome, which is passed on from father to son.
In other words, a king may have been cuckolded, his wife giving birth to another man’s child.
“If they have been able to reliably trace male-line relatives with solid genealogical evidence then Y chromosome analysis would definitely be the way to go with the caveat that there could have been a false paternity, or paternities, along the way,” Turi King, a geneticist at the University of Leicester who carried out the DNA analysis on King Richard III, told Discovery News.
“If I was going to do the DNA for this, I’d want to test a number of distantly related men from the tree and see if their Y chromosomes match such that we’d expect,” King said.
“If they do, the higher up the tree they all connect (have a common ancestor) the better. In this way you can feel a bit safer, but not completely, that this is Da Vinci’s Y chromosome type,” she added.
Read more at Discovery News
The controversial archaeologist, Semir Osmanagich, wrote in a blog that the sphere dates back more than 1,500 years and is “the most massive stone ball in Europe.” He estimates the sphere weighs some 30 tons or more.
Osmanagich said he discovered the sphere in the village of Podubravlje, near Zavidovici, Bosnia and Herzegovina, and his estimates show it has a radius of between 1.2 to 1.5 meters (about 3 feet, 11 inches to about 4 feet, 11 inches).
He says the sphere, in addition to his earlier claims that Bosnia is home to hidden ancient pyramids linked by underground tunnels, prove the existence of an advanced, lost civilization.
“It would be another proof that Southern Europe, Balkan and Bosnia, in particular, were home for advanced civilizations from distant past and we have no written records about them,” Osmanagich wrote in the blog post announcing the discovery for his non-profit group named The Archaeological Park: Bosnian Pyramid of the Sun Foundation.
Other archaeologists have dismissed Osmanagich’s previous claims about pyramid finds. Anthony Harding, President of the European Association of Archaeologists, described the claims as “complete fantasy.”
According to the International Business Times, some archaeologists have already dismissed Osmanagich’s sphere discovery saying that the rock was likely created naturally. Mandy Edwards of the University of Manchester's School of Earth, Atmospheric and Environmental Sciences told the Daily Mail that the rock was likely formed by the "precipitation of natural mineral cement within the spaces between sediment grains."
Could Osmanagich's new discovery be manmade?
Stone balls have been discovered around the world and linked to ancient civilizations. There are ancient volcanic stone spheres in western Mexico, stone balls in the small island in Pacific – Isla del Cano, volcanic stone balls on Easter Island, and others in Tunisia, and the Canary Islands.
Among the most famous of these finds are the more than 300 granite balls uncovered in Costa Rica. Each weighs up to 14 tons and were linked to the now extinct Diquis culture. In June 2014, the Stone Spheres of the Diquis was added to the UNESCO list of World Heritage Sites.
Osmanagich stands by his theory that his recent find could represent the biggest, manmade stone ball of them all. He added that his team has located stone balls in several other locations in Bosnia.
“We found granite stone balls in the Teocak village in northeastern Bosnia, volcanic stone ball near town of Konjic in middle Bosnia and sandstone stone spheres in many locations in western and middle Bosnia,” Osmanagich wrote.
Read more at Discovery News
In 2014, the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile observed a striking cosmic quirk during its Long Baseline Campaign. It saw a distant galaxy, warped beyond recognition, by the gravitational field of a massive galaxy in the foreground. This “Einstein ring” is so-called after Einstein’s theory of general relativity, which predicts spacetime can become bent by the presence of a powerful gravitational field.
In this case, the foreground galaxy had drifted in front of the more distant galaxy located some 12 billion light-years away, causing the distant galaxy’s light to be redirected around the warped spacetime. The result was a near-perfect circle of galactic light received by ALMA as one of the more extreme examples of gravitational lensing. Gravitational lensing is common in observations of the deep cosmos, where massive galaxies and galactic clusters bend spacetime like a malleable rubber sheet, often creating a “funhouse” mirror-like effect, distorting the observed shapes of distant galaxies whose light has taken a helter-skelter path through the confused spacetime landscape.
But sometimes, as this example proved, the alignment can be so perfect that the distant galaxy’s light can be warped around the symmetrical foreground galaxy, creating a ring that resembles a candle flame passing behind a magnifying glass. Gravitational lenses are the universe’s natural magnifying lenses and they are being used by the Hubble Space Telescope, for example, to superboost its observational power as part of the Frontier Fields project.
Though it looks like a pristine ring, this particular observation of the “SDP.81″ gravitational lens holds some tiny distortions in the shape of its ring and astronomers have used these distortions to reveal the presence of an invisible dwarf galaxy situated right next to the more massive lensing galaxy. And this tiny cluster of stars is packed with dark matter.
“We can find these invisible objects in the same way that you can see rain droplets on a window,” said Yashar Hezaveh at Stanford University, Calif., in a statement. “You know they are there because they distort the image of the background objects.” Raindrops will subtly refract light, distorting the light passing through a window; in much the same way, the invisible dwarf galaxy’s gravitational field is creating a minute distortion in the Einstein ring, revealing its presence in a tiny spacetime warp.
Finding this distortion and realizing it was due to the presence of an unseen galaxy was no easy task and required a huge computational effort, requiring, in part, time on one of the world’s most powerful supercomputers, the National Science Foundation’s Blue Waters.
Because of its close proximity to the larger galaxy, its estimated mass and lack of optical data, Hezaveh’s team thinks they’ve found a very dim dwarf galaxy that is dominated by dark matter.
Read more at Discovery News
This could be a possible explanation for why nothing is seen within the orbit of Mercury, although for now the evidence is based on modelling and the fact that the region between Mercury and the sun is so barren, the authors say.
“The only (physical) evidence that super-Earths could have formed in our solar system is the lack of anything in that region, not even a rock,” said lead author Rebecca Martin, an assistant professor at the University of Nevada, Las Vegas, in an email to Discovery News. ”So they could have formed there sweeping up all of the solid material, but then later fell into the sun.”
Observations of super-Earth exoplanets outside the solar system suggest they could have formed in two locations: in situ (where you see them today) or farther out from their observed locations, where of course they would have migrated over time.
|Mercury transits the sun as seen by the Solar and Heliospheric Observatory in 2006. Credit: Mercury transits the Sun as seen from Earth in 2006.|
“The size of the dead zone must be large enough that it lasts for the entire disc lifetime,” Martin added. “Since different systems may have different dead zone sizes, formation in the inner parts may not be possible in all systems and thus both formation locations may be operating.”
Of the super-Earths that have been observed, the researchers noted two distinct types depending on their density. They conclude that planets that form farther out in the disc would be less dense, since water and other volatiles will freeze out in the cooler outer parts of the disc. Those that are closer one would be denser.
Read more at Discovery News
Apr 13, 2016
Using the brilliant light of the overhead sun as a backdrop, NASA researchers have developed a patent-pending method called Background-Oriented Schlieren using Celestial Objects (BOSCO) to make atmospheric distortions from supersonic shockwaves visible.
Invented in 1864 by German physicist August Toepler, who developed the technique by photographing electric sparks in a lab, modern air-to-air schlieren photography uses high-speed, high-definition cameras and advanced imaging software to average out background noise and reveal the shockwaves.
(Schlieren comes from the German word for “streak.”)
In the crop below the side view of the T-38C can be made out, along with the light coming through the cockpit.
Read more at Discovery News
In a study out of Monash University and Australia’s Museum Victoria, researchers examined the 26-million-year-old ear bone of a xenorophid whale, one of the earliest ancestors of modern toothed whales — a group that includes dolphins as well as sperm whales, beaked whales and porpoises.
Using CT scanning, the scientists were able to view the ear bone’s structures in sharp detail.
The cochlea of the ancient animal, the team found, was specialized for the ability to sense high-frequency sound. And that looked familiar.
“When I first looked at the inner ear of the xenorophid, I was blown away by just how similar this incredibly old toothed whale was to a modern echolocating dolphin,” said study lead Travis Park, of Monash University and Museum Victoria, in a statement.
Echolocation allows some animals, such as bats and dolphins, to emit sounds and use their return echoes to map things in their world — from prey to predator to inanimate object. It’s a kind of “sight” that’s considered an evolutionary advantage that helped animals in the toothed whale category spread and diversify across the Earth.
The similarity between the ancient toothed whale’s inner ear and that of today’s dolphin, the researchers say, solves a long-running mystery of just when dolphins first evolved their ability to echolocate.
The finding also confirmed that ancient toothed whales could echolocate at all.
Researchers had previously thought the creatures could make high-frequency sounds. “But no one had actually ever looked to see whether they could actually hear these high frequency sounds as well,” as Park told ABC Online’s Rachel Brown.
Still unanswered, say the scientists, is what came before these super-sonic marine mammals.
“Our paper shows even the earliest known fossil odontocetes [toothed whales] have all the tools for echolocation seen in living dolphins,” said study co-author Erich Fitzgerald, of Museum Victoria. “But they must have evolved from something that didn’t quite have all the tricks of the odontocete trade.”
Read more at Discovery News
The red and black cave drawings contained in the cave are more than 30,000 years old, according to a radiocarbon dating study published this week in the Proceedings of the National Academy of Sciences, a peer-reviewed US journal.
The cave is located in Vallon-Pont d’Arc, Ardeche, and was classified as a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site in 2014, 20 years after it was first discovered.
“What is new in our study is that we have established the chronology of the cave for the first time in calendar years,” said Anita Quiles, a scientist at the French Institute for Oriental Archaeology in Cairo.
Because of stylistic similarities, researchers had long believed that the Chauvet art was from about the same period as that contained in Lascaux, a prehistoric site in southwestern France that dates to 20,000 years ago.
“But now we know there is 10,000 years — or even 15,000 years — of a split in the dates of these two sites,” she told AFP.
“We can now say with certainty that there has been no human activity in the Chauvet cave for about 30,000 years.”
The study analyzed charcoal samples on the cave floor and walls, and found that there were two phases of human occupation.
The first lasted from 37,000 to 33,500 years ago, said the study, appearing to come to an end around the time of a rockfall in one section of the cave.
The second wave of human occupation lasted from 31,000 to 28,000 years ago.
“The end of the second human occupation correlates with a second rockfall 29,400 years ago that partially closed off the cave entrance,” said the study.
Researchers also analyzed animal bones found in the cave and identified them as belonging to cave bears.
No human remains have been found inside, and experts believe this is because people did not live in the cave but rather visited from time to time.
The artwork contains 447 drawings of animals, including deer, horses and rhinoceroses.
Read more at Discovery News
But rather than focusing on those who succumbed to illness, they looked at an even smaller sub-group who beat the odds and remained healthy.
These people were born with a genetic predisposition towards developing serious and debilitating conditions such as cystic fibrosis, but something in their genomes caused them to still be resistant to the illnesses.
The researchers found 13 individuals who they believed could hold the answer to beating a range of illnesses.
But they were not able to contact the unnamed people because of consent rules signed by the study participants.
Stephen Friend from the Mount Sinai Hospital’s Icahn School of Medicine launched the project in 2014 with a global crowd-sourcing appeal for access to people’s DNA samples.
Ultimately the project was able to gain access to hundreds of thousands of DNA samples, provided voluntarily to testing laboratories by individuals from around the world who had agreed their samples could be used for research.
“Basically all we need is information, we need a swab of DNA and a willingness to say, ‘what’s inside me?’” Friend said in a 2014 TED Talk.
The research is part of a pilot study for what’s been dubbed “The Resilience Project”.
Friend and his team have now launched a follow-up project in which participants will submit their genetic data with the understanding they will be recontacted.
Bob Williamson from the University of Melbourne, the former director of the Murdoch Children’s Research Institute, is pleased researchers are focusing on the healthy, not just the sick.
“We spend all of our time looking at people who are sick and don’t take into account that many people are very healthy indeed,” he said.
“And this is sometimes in spite of the fact that they have a genetic mutation which in many people will cause the disease.”
Williamson said the work promised to create an extraordinary data bank of material for ongoing medical research.
“Cystic fibrosis is a disease that we assumed would be caused by a mutation and there was just no way around it,” he said. “And yet they found people who had the mutations that cause cystic fibrosis, and because of other genes, because of other mutations, they did not develop the disease.
“Now this is really exciting because of the perspective it puts on human genetics.”
Williamson said the information could be used to design new drugs to treat people who do develop diseases like cystic fibrosis.
Read more at Discovery News
The system is called WASP-47 and actually has three planets close in to the star: a hot Jupiter, a hot super-Earth and a hot Neptune. Meanwhile, the other 100-or-so hot Jupiters found don’t have any (detected, at least) super-Earth companions. What is up with that?
A new study proposes that it’s very hard to find both in the same system because super-Earths get very easily destroyed.
“I argue that the lack of super-Earth companions to hot Jupiters is evidence that most of these planets have experienced strong gravitational effects from other planets or stars in the past: they are sent onto highly eccentric orbits like those of comets, and then their orbits circularize over time,” said lead author Alexander James Mustill, a senior astronomy and physics research fellow at Lund University in Sweden, in an email to Discovery News.
“During the phase of high eccentricity, they destroy any super-Earths orbiting close to the star, usually by forcing them to collide with the star or with the planet itself.”
A part of his paper, for example, looked at what happens with planets that are very hard to see — that is, the planets that orbit far away from their star and don’t tug on it as strongly (or pass across it as frequently.) These are the main techniques for detecting planets.
“I take the close-in systems of super-Earths and ask what would happen if I add various extra bodies on wide orbits to the system, such as giant planets like Jupiter, or binary stars,” Mustill said.
“I find that in about 25 percent of these systems, the super-Earths will be destabilized and begin colliding with each other. Answering the inverse problem: given what we observe about the super-Earth systems, how many have some outer giant planets, is a much trickier question, and the work is still ongoing.”
Read more at Discovery News
Apr 12, 2016
Unexpected long-range particle interactions: Spinning cells could attract each other across surprisingly long distances
Scientists have known for a long time that small particles of matter, from the size of dust to sand grains, can exert influences on each other through electrical, magnetic, or chemical effects. Now, this team has found a new kind of long-range interaction between particles, in a liquid medium, that is based entirely on their motions. And these interactions should apply to any kind of particles that move, whether they be living cells or metal particles whirled by magnetic fields.
The discovery, which holds for both living and nonliving particles, is described in a paper by Alfredo Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering at MIT, and his co-researchers, in the Proceedings of the National Academies of Sciences.
Alexander-Katz describes the kind of interactions his team found as being related to the research field of active matter. Example of active systems are the flocking behavior of birds or the schooling of fish. Each individual member of the system may be responding just to others in its vicinity, but the result is a coherent overall pattern of movement that can span a large region. Cells in a fluid medium, or even tiny structures moving within a cell, exhibit similar kinds of motion, he says.
The researchers studied magnetic particles a few micrometers (millionths of a meter) across, comparable to the size of some cells. A small number of these magnetic metal microparticles were interspersed with a much larger quantity of inert particles of comparable size, all suspended in water. When a rotating magnetic field was applied, the metal particles would begin to spin, simulating the movements of living cells in the midst of nonliving or relatively inert objects -- such as when cells migrate through tissues or move in a crowded environment.
They found that the spinning particles, even when separated by distances tens of times their size, would ultimately migrate toward each other. Though that attraction progressed through a slow and apparently random series of motions, the particles would in the end almost always come together.
While there has been a lot of research on interactions among active particles, Alexander-Katz says, this is one of the few studies that has looked at the way such particles interact when they are surrounded by inactive particles. "In the absence of the inactive particles there are essentially no interactions," he says.
The unexpected finding might ultimately lead to a better understanding of the behavior of some natural biological systems or new methods for creating synthetic active materials which could be useful for selectively delivering drugs into certain parts of the body, Alexander-Katz suggests. It could also end up finding applications in electronics or energy-harvesting systems, for example providing a way to flip a crystal structure between two different configurations.
"What we're addressing is collective excitations of the system, or coherent excitations," he explains. "What we're looking at is, what are the interactions as a function of activity" of the individual particles.
The faster the particles spin, the greater the attraction between them, the team found. Below a certain speed the effect stops altogether. But the amount of inert matter also makes a difference, they found.
With no inert particles -- if the moving particles are suspended in clear water -- there is no motion-based attraction. But when the nonspinning particles are added and their concentration reaches a certain point, "there is attraction!" Alexander-Katz says.
One unexpected aspect of the findings was how far the effect extended. "What was really surprising was that the range of the interactions is gigantic," he says. By way of comparison, he says, imagine you're in a crowd, and you start to move a bit, and someone else also starts to move, while everyone else tries to stand still. "I would be able to sense, even 20 people away or more, that that person is also active -- assuming that the other folks around us are not active."
The attraction, he says, "is not chemical, it is not magnetic, it is not electrostatic, it's just based on activity." And because the range is so long, these interactions could not be modeled in simulations but required physical experiments to be uncovered. The tests by Alexander-Katz and his team used two-dimensional films, similar to particle sediments that form on a rock surface, he says.
Read more at Science Daily
The swarm, consisting of thousands of red crabs, represents a new southernmost range for the species, Pleuroncodes planipes. Researchers aboard the submersible Deep Rover 2 were both astounded and mesmerized by the unexpected sight, which they recorded about 1,200 feet below the ocean’s surface.
“When we dove down in the submarine, we noticed the water became murkier as we got closer to the bottom,” project leader Jesús Pineda, a biologist at Woods Hole Oceanographic Institution, said in a press release. “There was this turbid layer, and you couldn’t see a thing beyond it. We just saw this cloud but had no idea what was causing it.”
“As we slowly moved down to the bottom of the seafloor, all of the sudden we saw these things,” he continued. “At first, we thought they were biogenic rocks or structures. Once we saw them moving — swarming like insects — we couldn’t believe it.”
Genetic testing identified the crab species, which is known to be abundant off the coast of Baja California. Apparently the crustaceans have a secret life further south too. Information about the discovery is published in the journal PeerJ.
Pineda and his team encountered the swarm while studying the Hannibal Bank Seamount off the Panamanian coast. Seamounts are underwater mountains that usually rise at least 3,280 feet above the ocean floor.
The large aggregation of red crabs was observed along the Northwest flank of the seamount in acidic water with very low levels of oxygen.
“These crabs have been detected before in similar low oxygen conditions,” Pineda explained. “It could be that these low oxygen waters provide a refuge for this species from predators.”
The frenzy to stay in this crowded spot makes sense when considering the nickname for these crustaceans: tuna crabs. Yellowfin tuna love to eat them, as do many birds, marine mammals and other fish. Humans can eat them too, but do so at risk. That is because the crab’s food source consists of phytoplankton that can contain high levels of toxins.
Read more at Discovery News
It was believed that no traces were left of the painter, engineer, mathematician, philosopher and naturalist. The remains of Leonardo, who died in 1519 in Amboise, France, were dispersed in the 16th century during religious wars.
But according to historian Agnese Sabato and art historian Alessandro Vezzosi, director of the Museo Ideale in the Tuscan town of Vinci, where the artist was born in 1452, Da Vinci’s family did not go extinct.
“We carried out long archival research, which is the first step of a broader scientific investigation,” Vezzosi told Discovery News.
“We checked documents and tombs as far as France and Spain in order to reconstruct the history of Leonardo’s family,” he added.
Vezzosi and Sabato identified the direct living descendants from Leonardo’s father, a Florentine legal notary named Ser Piero Da Vinci.
“The implication of our discovery is that scientists may be able to isolate Da Vinci’s DNA, 15 generations later,” Vezzosi said.
The researchers will detail their discovery at a conference on Thursday, just a day before the 564th anniversary of Da Vinci’s birth. Some of Leonardo’s descendants will attend the conference.
“The list includes some surprising names,” Vezzosi said.
From Discovery News
Similar to how Native Americans had no evolved immunity for diseases brought over by Europeans, Neanderthals and other archaic humans from Europe and Asia are believed to have had no evolved immunity for diseases brought over by migrating anatomically modern humans from Africa.
“Humans migrating out of Africa would have been a significant reservoir of tropical diseases,” co-author Charlotte Houldcroft said in a press release. “For the Neanderthal population of Eurasia, adapted to that geographical infectious disease environment, exposure to new pathogens carried out of Africa may have been catastrophic.”
Houldcroft, from the University of Cambridge’s Division of Biological Anthropology, and her colleagues reviewed the latest evidence gleaned from pathogen genomes as well as from ancient bone DNA. The scientists concluded that some infectious diseases are likely to be many thousands of years older than previously believed. Their findings are reported in the American Journal of Physical Anthropology.
The longstanding view about the evolution of major human diseases has been that most emerged and spread with the dawn of agriculture around 8,000 years ago. The scientists, however, determined that there was a much longer “burn in period” for human diseases that pre-dates agriculture.
Houldcroft explained that genetic data shows many infectious diseases have actually been “co-evolving with humans and our ancestors for tens of thousands to millions of years.”
What’s more, numerous diseases traditionally thought to be “zoonoses,” (transferred from animals into humans), turn out to have human origins.
The scientists suspect that the migrating humans brought with them tapeworm, tuberculosis, stomach ulcers and types of herpes that could have all spread to Neanderthals. Prior research shows that modern humans interbred with Neanderthals, proving that individuals from these groups were in close contact with each other at least for certain periods.
While these illnesses are not necessarily fatal, the researchers believe that the Neanderthals lacking immunity could have grown weak and less able to find food, which could have catalyzed their extinction.
It does not appear that Neanderthals spread disease to the humans from Africa. It was just the opposite. The interbreeding benefited our species since we received genetic components through interbreeding that protect against types of bacterial sepsis (blood poisoning occurring from infected wounds) and encephalitis caught from ticks that inhabit Siberian forests.
The interbreeding means that a small percentage of Neanderthal DNA lives in all people today of European and Asian heritage. As a result, Neanderthals were absorbed into the modern human population. As a physically and culturally distinct group, however, the Neanderthals died out.
Recent studies indicate that some early Native American lineages might have died out too, following European colonization of the Americas. Comparisons to what happened to the Native Americans only go so far, though, given that Neanderthals are thought to have lived in small groups spread out over large distances.
Read more at Discovery News
These black holes, which occupy the centers of galaxies in a region of space called ELAIS-N1, appear to have no relation to one another, separated by millions of light-years. But after studying the radio waves generated by the twin jets blasting from the black holes’ poles, astronomers using data from the Giant Metrewave Radio Telescope (GMRT) in India realized that all the jets were pointed in the same direction, like arrows on compasses all pointing “north.”
This is the first time a group of supermassive black holes in galactic cores have been seen to share this bizarre relationship and, at first glance, the occurrence should be impossible. What we are witnessing is a cluster of galaxies, that all have central supermassive black holes that have their axes of rotation pointed in the same direction.
“Since these black holes don’t know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe,” said Andrew Russ Taylor, director of the Inter-University Institute for Data Intensive Astronomy in Cape Town, South Africa. Taylor is lead author of the study published in the journal Monthly Notices of the Royal Astronomical Society.
In other words, though each of these galaxies are currently independent from one another, they likely originated from the same small-scale mass fluctuation, shortly after the Big Bang, and therefore used to have some commonality on a quantum scale. These objects were all spawned in the same compact region of primordial space some 13.8 billion years ago that, as the universe expanded, drifted apart into the mature galaxies we see today in that distant volume of space.
But the fact they remain highly correlated provides an incredible opportunity for astronomers to see how the small scale structure of the early universe influenced the large-scale structure of our universe today.
The researchers hope to use this surprising discovery to perhaps better understand the conditions in which they formed, but the discovery will be a huge challenge to explain as there’s no cosmological model that can currently account for it.
“This is not obviously expected based on our current understanding of cosmology. It’s a bizarre finding,” said collaborator Romeel Dave, of the University of the Western Cape, South Africa.
Needless to say, the researchers have plenty of hypotheses about what influenced the primordial universe to produce such a fine-tuned group of black holes. Perhaps powerful magnetic fields influenced primordial matter in such a way to seed the group of synchronized black holes. Maybe the influence of a hypothetical dark matter particle (such as axions) had a role to play or cosmic strings might have somehow influenced their evolution. For now, it’s anyone’s guess.
Read more at Discovery News
Apr 11, 2016
The added species, mostly bacteria and single-celled microorganisms known as Archaea, show that much of the life that we see around us represents just a tiny percentage of the world’s biodiversity.
“The tree of life is one of the most important organizing principles in biology,” Jill Banfield of the University of California at Berkeley said in a press release. “The new depiction will be of use not only to biologists who study microbial ecology, but also biochemists searching for novel genes and researchers studying evolution and earth history.”
The new tree of life and related findings are published in the latest issue of the journal Nature Microbiology.
Charles Darwin first sketched a tree of life in 1837 as he sought ways of showing how plants, animals and bacteria are related to one another. The tips of the twigs on such images represent life on Earth today, while the branches connecting them to the trunk indicate evolutionary relationships.
A branch that divides into two twigs near the tips of the tree shows that these organisms have a recent common ancestor, while a forking branch close to the trunk implies an evolutionary split in the distant past.
But Darwin knew nothing of the newly added microorganisms, which before their discoveries over the past 15 years were lurking unseen in Earth’s nooks and crannies. It was only after the genome revolution that technical advances permitted Banfield and others to search for other life forms directly in the field, as opposed to trying to culture them in a lab dish.
It would be to find some of the new organisms in a lab dish anyway, since many microbes cannot be isolated and cultured. That is because they cannot live on their own. They must beg, borrow or steal from other animals or microbes, either as parasites, symbiotic organisms or scavengers.
“Bacteria and Archaea from major lineages completely lacking isolated representatives comprise the majority of life’s diversity,” said Banfield, who also works at the Lawrence Berkeley National Laboratory. “This is the first three-domain genome-based tree to incorporate these uncultivable organisms, and it reveals the vast scope of as yet little-known lineages.”
Read more at Discovery News
The findings, published in the journal Proceedings of the National Academy of Sciences, help resolve a longstanding debate over whether the first major phase of biblical text compilation took place before or after the destruction of Judah’s capital city, Jerusalem, in 586 B.C.
The new research concludes that early sacred texts of the Torah, known in part to Christians as the Old Testament, were written shortly before that fateful event, when Babylonian king Nebuchadnezzar destroyed Jerusalem and forcibly exiled the people of Judah.
“Several (biblical) texts refer to events which best fit the reality in the years just before the fall of the Kingdom of Judah,” senior author Israel Finkelstein, a professor of archaeology at Tel Aviv University, told Discovery News.
For the study, Finkelstein, lead author Shira Faigenbaum-Golovin and their team used novel image processing and computer analysis to investigate 16 inscriptions from the desert fortress of Arad, located west of the Dead Sea. The inscriptions, which are correspondence concerning military matters, date to 600 B.C. and were made by putting ink script on ceramic shards.
“This was a common practice at the time,” Finkelstein explained. “We know this from other Judahite forts, both in the Negev (the south) and the Shephelah (the west). Most of the inscriptions deal with mundane issues, such as orders to send commodities to or with army units.”
In this case, the inscribed shards -- known as ostraca -- contain military commands regarding the movement of troops and provision of wine, oil and flour among the men. One mentions “the king of Judah” and another “the house of YHWH,” in reference to the Temple in Jerusalem.
Faigenbaum-Golovin and colleagues Arie Shaus and Barak Sober focused their analysis on who wrote the correspondence. They determined that six individuals of varying military ranks created the ostraca.
In terms of who wrote these earliest biblical works, Finkelstein said, “The first Judahite biblical texts were most probably put in writing in Jerusalem by priests and officials in the entourage of the king, possibly King Josiah. The ideology and theology of Judah in his days was supported by two platforms of written texts: the law (Deuteronomy) and the history (the Book of Joshua to 2 Kings).”
Since the earliest biblical texts represent the political and theological ideologies of their authors, he said “it makes sense that at least the literati could read them. If a large number of people could read the text, it could have been easier to distribute the ideas of the authors among the Judahite population of the time.”
Christopher Rollston, an associate professor of Northwest Semitic languages and literatures at George Washington University, agrees that the period around 600 B.C. was a time “of prolific literary activity, with large portions of books such as Joshua, Judges, and 1–2 Kings written during this period. This is also the same time frame as that of the Prophet Jeremiah (included in the Torah/Old Testament) and his famous scribe Baruch.”
Rollston, however, believes other inscriptional evidence from the region dates to the late 9th and 8th centuries B.C., and therefore thinks “that some portions of the Bible could have been written even earlier than the Tel Aviv study suggests.”
Even with this still existing debate, the new research at least helps to settle an important matter about the timing of the Bible’s first compilation phase.
Read more at Discovery News
The roughly 1,600-year-old kilns served the entire Roman Empire, according to a statement by the Israel Antiquities Authority (IAA). They indicate that “the Land of Israel was one of the foremost centers for glass production in the ancient world,” the IAA said.
“We know from historical sources dating to the Roman period that the Valley of Akko was renowned for the excellent quality sand located there, which was highly suitable for the manufacture of glass,” said Yael Gorin-Rosen, head curator of the Israel Antiquities Authority Glass Department.
She noted that chemical analyses conducted on glass vessels from this period which were discovered at sites in Europe and in shipwrecks in the Mediterranean basin pointed to Israel as the source of the glass.
“Now, for the first time, the kilns have been found where the raw material was manufactured that was used to produce this glassware,” she said.
Dating to the Late Roman period, the kilns were discovered by chance last summer at a site near Haiifa before the construction work that was part of the Jezreel Valley Railway Project.
“We exposed fragments of floors, pieces of vitrified bricks from the walls and ceiling of the kilns, and clean raw glass chips. We were absolutely overwhelmed with excitement when we understood the great significance of the finds,” said archaeologist Abdel Al-Salam Sa’id, an inspector with the Israel Antiquities Authority.
Further excavation revealed the production site consisted of two compartments. There was a firebox where kindling was burned to create a very high temperature, and a melting chamber in which clean beach sand and salt, the raw materials for the glass, were inserted and melted together at a temperature of about 2,200 Fahrenheit degrees.
The glass was heated for a week or two until enormous chunks of raw glass were produced, some of which weighed over 10 tons.
At the end of the manufacturing process the kilns were cooled and the large glass chunks that were manufactured were broken into smaller pieces and sold to workshops where they were melted again in order to produce glassware.
We know from a price edict circulated by the Roman emperor Diocletian in the early fourth century A.D., that there were basically two kinds of glass: the light green Judean glass, from Israel, and the more expensive Alexandrian glass from Egypt.
Read more at Discovery News
In the decades since Lawrence published the memoir “Seven Pillars of Wisdom” describing his wartime experiences, critics have accused him of exaggerating or even falsifying his participation in certain events. For instance, some biographers have said he embellished his role in the Hallat Ammar train ambush, recognized by historians as a clash that helped define tactics used in modern guerilla warfare.
But now, archaeologists have discovered a piece of evidence that appears to place Lawrence at the scene of the ambush. It’s not quite a “smoking gun,” but it’s the next best thing — a bullet fired from a Colt 1911 automatic pistol, a gun that Lawrence was known to have carried.
A distinctive weapon
That type of gun was unlikely to have been used by anyone else at the ambush, said archaeologist Nicholas Saunders, one of the leaders of the team that investigated the site. Saunders co-directs the Great Arab Revolt Project (GARP), whose members have excavated a number of Arabian Desert locations where key battles were fought during the Arab Revolt between 1916 and 1918.
A Jordanian army escort accompanied Saunders and his team during their work on the ambush site, which lies in a demilitarized zone between Saudi Arabia and Jordan. A metal detector led the researchers to the bullet, Saunders told Live Science in an email.
Though the bullet was clearly different from the hundreds of other expended cartridges at the site, the archaeologists didn’t recognize the find’s significance right away, Saunders said. Handgun experts on the team conferred with an international network of specialists to identify the bullet as originating from a Colt 1911 automatic pistol, rather than from a rifle or other pistol of British, German or Turkish make that accounted for most of the spent ammunition the researchers found.
“It was the only Colt 1911 bullet found at Hallat Ammar,” Saunders said, adding that Lawrence was the only person known to carry one of these guns during the ambush.
Read more at Discovery News
Apr 10, 2016
And while that cycle isn’t going away, climate change is messing with the axis upon which our fair planet spins. Ice melting has caused a drift in polar motion, a somewhat esoteric term that tells scientists a lot about past and future climate and is crucial in GPS calculations and satellite communication.
Polar motion refers to the periodic wobble and drift of the poles. It’s been observed for more than 130 years, but the process has been going on for eons driven by mass shifts inside the earth as well as ones on the surface. For decades, the north pole had been slowly drifting toward Canada, but there was a shift in the drift about 15 years ago. Now it’s headed almost directly down the Greenwich Meridian (sorry Canada no pole for you, eh).
Like many other natural processes large and small, from sea levels to wildfires, climate change is also playing a role in this shift.
“Since about 2000, there has been a dramatic shift in this general direction,” Surendra Adhikari, a researcher at NASA’s Jet Propulsion Laboratory, said. “It is due to climate change without a doubt. It’s related to ice sheets, in particular the Greenland ice sheet.”
That ice sheet has seen its ice loss speed up and has lost an average of 278 gigatons of ice a year since 2000 as temperatures warm. The Antarctic has lost 92 gigatons a year over that time while other stashes of ice from Alaska to Patagonia are also melting and sending water to the oceans, redistributing the weight of the planet.
Adhikari and his colleague Erik Ivins published their findings in Science Advances on Friday, showing that melting ice explains about 66 percent of the change in the shift of the Earth’s spin axis, particularly the rapid losses occurring in Greenland.
It’s a huge, mind boggling process on the global scale, but imagine it like a top. Spinning a top with a bunch of pennies on it will cause wobble and drift in a certain pattern. If you rearrange the pennies, the wobble and drift will be slightly different.
That’s essentially what climate change is doing, except instead of pennies, it’s ice and instead of a top, it’s the planet. Suffice to say, the stakes are a little higher.
Ice loss explains most but not all of the shift. The rest can mostly be chalked up to droughts and heavy rains in certain parts of the globe. Adhikari said this knowledge could be used to help scientists analyze past instances of polar motion shifts and rainfall patterns as well as answer questions about future hydrological cycle changes.
Ice is expected to continue melting and with it, polar motion is expected to continue changing as well.
“What I can tell you is we anticipate a big loss of mass from West Antarctic and Greenland ice sheets and that will mean that the general direction of the pole won’t go back to Canada for sure,” Adhikari said.
Read more at Discovery News
The waxing crescent moon, 15 percent illuminated by the sun, will pass in front of the star that marks the angry orange eye of the constellation Taurus, also known as the Bull.
That star is Aldebaran, the 13th brightest star in the sky and certainly one of the more colorful ones. This eclipse is known to astronomers as a lunar occultation. As the moon orbits the Earth, it appears, from our perspective, to move slowly toward the east relative to the stars, at roughly its own diameter per hour. A waxing moon always leads with its dark edge as it moves along its orbit against the starry background.
However, there is a catch: Across most of its viewing range, the moon will be crossing in front of the star during the daytime.
Some skywatchers may think that this will preclude them from seeing the occultation, but that’s not necessarily so. While you certainly will not be able to see it with your unaided eye, if you’re looking just prior to when it vanishes behind the moon, a good pair of binoculars or a small telescope should allow you to pick out Aldebaran against the blue daytime sky.
Of course, your ability to see it will be strongly dependent on your local weather. If, for instance, the sky is hazy or if there are thin or high clouds passing across your line of sight as Aldebaran is about to duck out of sight behind the moon, you probably will not see it. In fact, your first hurdle would be to locate the moon itself. It will be located about 50 degrees to the east (left) of the sun. Your clenched fist held out at arm’s length measures roughly 10 degrees, so look for the moon approximately “five fists” to the left of the sun.
If the sky in your area is deep blue — which usually happens after the passage of a cold front or storm system accompanied by rain to “cleanse” the sky of any clouds or haze — you have a better chance of observing this skywatching event.
And if you do glimpse Aldebaran in your binoculars or telescope, keep in mind that it will disappear behind the moon’s unilluminated portion first. In deep twilight or darkness, you would be able to see the dark part of the moon approach the star by virtue of earthshine — that dark portion would be dimly lit with a bluish-gray hue. But in the daytime, it’s completely invisible, so the star will suddenly seem to “click off” as if somebody had flipped a switch.
This table provides a listing for a dozen selected cities in the United States and Canada and the times when Aldebaran will disappear, and later reappear, from behind the moon. All times are in local daylight time, except for Honolulu. (Hawaii does not observe daylight saving time.)
If you live near or along the Atlantic Seaboard, the occultation will take place close to the time of sunset. In fact, from the northeastern United States, the time that Aldebaran is due to emerge back into view (along the moon’s bright edge) will take place after sunset in a twilight sky,making it a bit easier to see. And from the Canadian Maritime Provinces, both the disappearance and reappearance will occur after sunset.
Check out this table which provides listings for six selected cities in the northeastern United States and eastern Canada, and the times when Aldebaran will disappear and later reappear (after sunset) from behind the moon. The local time of sunset is included. All times are in local daylight time.
For those who are a bit more technically inclined, here is a link to the International Occultation Timers Association (IOTA) web page, which provides a map showing the region of visibility of the occultation, along with a comprehensive listing of times for nearly 600 locations in the United States, Canada, Mexico and the Caribbean. All times are in Universal Time (UT).
Read more at Discovery News